Vento 350

[Jon Pegler]

All the Ventos, Forzas and Stradas used points ignition with a 26 degree auto advance unit.( Not 28 as Italian)
No electronic ignition on these models.
All 12 volt Motoplat electrical systems though.

I can't remember what cam I put in a Vento years ago.
It did make the machine much more tractable for general riding.
I've got 450s with both 450SCR cams and Desmo cams.
The Vento with the Rapido cam will match them once the motor is really buzzing.

Jon

[Ventodue]

____ What?, "points & condensor" !? I thought all those Mototrans 350-models employed Spanish-made electronic-ignition systems !?

Tsk! Way too modern, Bob (see my earlier post - my Vento is still using points). The Forza wiring diagram that I posted also shows points.

But it's good question as to why. Jon - any idea? And do you know what the 500s use?

[Jon Pegler]

I don't know why Mototrans changed from electronic ignition on the motors they built for Bologna and the late 350 Road models.
It is also odd that they fitted a 26 degree auto advance unit to the Vento/Forza/Strada when they had used the 28 degree unit on the widecase 250 Road.
As far as I know, the 350 Road was always supplied with Motoplat electronic ignition.
The 500 parallel twins built in Spain also used points ignition.

Jon

[graeme]

Hello Jon,
A bit off topic sorry but which parallel twins were made in Spain?
Did they have Made in Spain written somewhere?

Muzz, I think I have a 450 scrambler cam spare if needed.

graeme

[DewCatTea-Bob]

I've got 450s with both 450SCR cams and Desmo cams.

____ I guess that's to be expected, since those are the two cams which were original-stock in most 450-models, even though neither cam was an actual '450 cam-model' (as both were really designed for other Duke-models). ...

I think I have a 450 scrambler cam spare if needed.

___ That statement probably ought to have been worded more like:
- If needed, I think I have a spare camshaft which came from a 450Scrambler. - ,
in order to be less misleading.
__ But if you actually have a REAL '450Scr.camshaft-model', then I-myself will gladly trade you something for it !
____ I should try to clear-up some details which otherwise may allow confusion concerning the camshafts of stock 450-models. ...
__ It's certainly understandable that somebody would naturally refer to the camshaft within their stock 450-DESMO as a '450Desmo-cam',, and likewise, also refer to the camshaft within their stock 450-Scrambler, as a '450SCR-cam'...
However, the DESMO-camshaft within all stock 450DESMO-models is ACTUALLY the '250DESMO-cam', as that 'Blue&White' color-coded camshaft-model was originally designed specifically for the 250-engine, (but was also employed for the 350 & 450 DESMO-engines as well, due to mass-production expense concerns).
And the camshaft which was original-stock for the springer-450s -(450-Scrambler & 450Mark-3 models), was FIRST employed for the late-1968 250-Scrambler model, so that particular cam-model really ought to be referred-to as the '68 250Scrambler-cam', (although I have reason to believe that THAT camshaft was possibly actually originally designed to be intended for the 350-Scr.model).
Anyhow, that w-c.Scrambler-cam probably should not be referred-to as the 250/450Scr.cam, because Ducati did design a specific scrambler-cam particularly intended for just the 450-Scrambler model,, and ALSO an-OTHER specific camshaft particularly intended for just the 450Mark-3 model !
Unfortunately I was never able to acquire either of those particular/REAL '450' cam-models for my collection of Duke-cams, but I do have SOME info concerning them... (for instance the v.timing on the [real!] 450Scr.cam-model is 50BT-75AB / 75BB-44AT , (in/ex respectively,, and the 450M3-cam.model had wilder v.timing with 12mm of lobe-lift [for the intake-lobe] ).
These two actual '450-cam.models' were available by 'Special order', and were not factory-installed due to cost-cutting concerns. _ Although I was once led to believe that the (real) 450Scr.cam-version was possibly originally installed in some (non-DESMO) 450-model production-run at the factory (sometime after 1970).
I've always wanted to acquire more complete data on these two ACTUAL 450-cam.models, but I suppose that it has become too late to find such anymore.
Anyone-else know of any related details on them ? - (If so, I'll may be able to tell if you're really on-to some REAL-info, as I do know a little more [for comparing it with].)


Hopeful-Cheers,
-Bob

[Jon Pegler]

Hi Graeme,

The Spanish produced versions of the 500 parallel twin, but not the 350.
One model was called a 'touring' machine and was a bit similar to the Italian GTL with a single downtube frame.
The 'sports' model was a Desmo and had a twin downtube frame.
Over the years the different models used either Telesco or Betor suspension.
The tank and side panels were in fibreglass and exclusive to the Spanish machines.
The mudguards were stainless and were the same as fitted to Forza and Strada singles.
Wheels were originally Italian FPS like the Desmo parallel twins made in Italy, but gave way to the 'speedline' used on the Vento and the late Forza. The very last ones used Akront demountable wheels ( a bit like a Honda comstar).
Most of the parallel twins produced in Spain had 'Made in Spain' on them somewhere.
They all had a sticker on the tank near the filler cap.
The 'speedline' copy wheels have made in Spain cast into them, as well as rim stickers each side.
Distinctively, most of the production machines have oil coolers, which the Italian ones do not and the Desmo models have a kickstarter as well as the electric start. Italian Desmos do not.
All told, they are quite different from the Italian built parallel twins in looks, if similar in performance.

Jon

[Muzz350]

Hi Bob
Lots of unusual things with the Spanish Ducati.
It has points but reversed ie: points closest to rear wheel. (No,not put in back to front or upside down as the holes in backing plate are concentric)
As for the magically acurate valve timing, if they were within 3deg I rounded them to the figures suggested in the manual. Also the carbi set up matches that cam especially the 50 slide and AB265 needle jet.
It also has a wider(thicker) bearing behind the drive sprocket with matching deeper recess in the case and no oil sling washer. I assume thats unusual?
Muz

[DewCatTea-Bob]

" Lots of unusual things with the Spanish Ducati. "

____ Apparently so.
__ I-myself have no direct experience with Mototrans-models not imported into the U.S.



" It has points but reversed "

____ Possibly so done to some-how better accommodate the unusual/odd entry-point manor at 1-o'clock for the associated wire-lead. _ (Perhaps Jon understands whatever the reasoning may have actually been for the need of that reversed arrangement.)
If the odd AAU is attached like past models, then flipping-around the AAU 180-degrees would've been an easy fix to match-up the cam-lobe location with the odd points-placement.



" As for the magically acurate valve timing, if they were within 3deg I rounded them to the figures suggested in the manual. "

___ Still, it seems somewhat rather off that only one reading was "8" degrees advanced.
It would've been interesting to know if the other three were all advanced also, (or randomly off-time by under 5-degrees).



" Also the carbi set up matches that cam especially the 50 slide and AB265 needle jet. "

____ Do you mean to allow indication that the Rapido-cam's carb.jetting is not the same ? _ Cuz I wouldn't have expected that such a difference in cam-models would've much mattered with such particular carb.jetting.



" It also has a wider(thicker) bearing behind the drive sprocket with matching deeper recess in the case and no oil sling washer. I assume thats unusual? "

____ Probably not for such newer w-c.models, as it seems to be a good update-mod.


Duke-Cheers,
-Bob
PS. I have posted an enlarged version of your lower posted-pic, (as it's rather small).

[graeme]

Hello Jon, thank you for the Spanish Ducati education. I didn't know they built parallel twins.

Hello Bob, appologies for my poor grammar

The 450 Scrambler cam I have came with a 450 engine which was in several boxes so I can't say if it is the cam that was in the head when it left the factory?
The cases didn't match either, the right side is a late wide cylinder bolt half and the right is an earlier narrow bolt model.
So I don't describe this "wide bolt" statement incorrectly, the bolts forward and rear of the cylinder hole. picture below,



The cam measures 21.8mm at the base circle and both lobes measure 30mm. There are 2 oil holes in each lobe.







I have a (supposedly) 1975 450 Scrambler (according to the numbers given to Srambler club in Italy) which will be restored in the future, I'll see if I can get the cam bearing holder off easily and get some idea of what cam is in that engine.

Hope this helps

graeme

[DewCatTea-Bob]

" Hello Bob, appologies for my poor grammar "

____ Well I had expected that you'd realize that "grammar" had nothing at all to do with my suggested rearrangement of your exact posted sentence-wording.
The expected point of the wording-change was to help keep it from being assumed that you may possibly have an ACTUAL/REAL '450Scrambler-cam', rather than the particular camshaft that came stock in 450-Scrambler models, as those two DIFFERENT camshafts are NOT the very-same cam-model !
__ I had expected that all my previous post-wording had made this fact clear enough to most every reader. _ But if not, then it's a good-thing that you've led me to reiterate my claimed fact, as being fully purposeful.


" The 450 Scrambler cam I have came with a 450 engine which was in several boxes so I can't say if it is the cam that was in the head when it left the factory? "

____ Okay then, that was certainly fair enough reasoning, (being an aspect I was unaware of),, however in that case, how could you then be any at all sure of WHAT-ever Duke-model the spare-cam may have actually come from !?
Oh-well, in any case,, it now seems certain that it was a GOOD presumption that the spare-cam actually originally came from a 450-model, (although likely not a REAL '450Scr.cam-model').
__ Anyhow, since you're STILL stating: "450 Scrambler cam", I thus-then feel the need to restate my point once again, that while such a 450Scr.cam-model really exist, it unfortunately did-NOT come stock within any 450-Scrambler imported into the U.S.A (at least).
I've already fairly well explained why no-one should refer to a 450-springer model's stock-cam, (which had originally came within a stock [non DESMO] 450-model), as a '450-Scrambler cam-model'.
If my previously posted-wording failed to make my (rather disconcerting) point perfectly clear, to ANYone,, then please ask for further clarification.



" The cases didn't match either, the right side is a late wide cylinder bolt half and the right is an earlier narrow bolt model. "

____ Boy-O-boy, SOMEone sure was desperate to scrap-together a 450 bottom-end !
I would've advised against such a mismatch of motor-case halves.



" The cam measures 21.8mm at the base circle and both lobes measure 30mm. "

____ I never recall min.base-circle or max.base-circle&lobe figures of any cam.model, since those figures can vary somewhat for any particular cam.model, (while the 'difference' between those two measured-figures always yields a particular cam.model's intended amount of lobe-lift).
__ I'm inclined to believe that you've likely obtained the correct b-c.+lobe figure of "30mm", however your other figure of "21.8mm" for the minimum 'base-circle' is suspect because it indicates that the lobe-lift of BOTH of the cam-lobes is identical at 8.2mm,, and,but the exhaust-lobe is always at least .2mm shorter than the intake-lobe.
So therefore I'm suspecting that you may-likely have measured at least one of the individual base-circles of the two separate cam-track/faces, incorrectly somehow.
Also,, when taking the cam-lobe's max.overall-measurement, it's worn track-face area should be avoided, and the usually near 1mm-wide unworn-area (at the edge of the peak of the lobe), is where your micrometer should get it's reading taken-from,, so as to better help identify the specific cam.model.


" I'll see if I can get the cam bearing holder off easily and get some idea of what cam is in that engine. "

____ After removing the four 6mm Allen-screws from the cam-bearing support/cover, then try using a long/thin rod in-through the center of the right-side/end of the camshaft, to then next tap on it until that cover has been pushed-out nearly an inch, and then twist the cover by hand to extract it outward the rest of the way (from it's place in the head).


____ I have adjusted your pix of your camshaft in question, and inserted them below along-with associated comments included.
__ After you've confirmed that you've correctly measured the absolute-MINIMUM 'min.base-circle' diameter of EACH of the two cam-tracks, then we will use your latest measurement-figures to confirm the specific cam.model of your presented camshaft.


Hopeful-Cheers,
-Bob